Known in the art, there is the U.S. Pat. No. 4,913,258 of Hiroshi Sakurai et al, granted on Apr. 3, 1990, in which there is described an outer-rotor type motor wheel, comprising a knuckle, a hub coaxially interlocked with the knuckle, a wheel disc rotatably attached to the periphery of the hub, a wheel secured to the periphery of the wheel disc, a rotor fastened to an outer side of the wheel disc from the direction of the outer side, and a stator coaxial to and spaced from the rotor by a small gap and fastened to the hub from the direction of the outer side. One drawback of this outer-rotor type motor wheel, is that in order to provide a powerful motor wheel having a high torque, high current has to be injected to the power line to energize the coil of the armature core even at zero speed. With this outer-rotor type motor wheel, a converter has to be provided. This converter is mounted inside the vehicule and can be very cumbersome. Such high current circulating through the power line produces heat which is energy loss and also requires a power line which can be quite heavy.
Also known in the art, there is the U.S. Pat. No. 754,802 of Ferdinand Porsche et al, granted on Mar. 15, 1904, in which there is described the combination of the axle, the wheel, the hollow journal for the wheel, the end of the axle projecting to the journal, and a pivotal connection between the axle and journal having its axial line disposed acutely to the plane of the wheel. Again, to produce a powerful motor-wheel, the current supplied to the sliding brushes, brought from outside of the motor-wheel has to be a high current. This high current will have to be brought through large diameter cables or wires to reduce energy loss.
Also known in the art, there is the U.S. Pat. No. 2,348,053 of J. E. Bowker, granted on May 2, 1944, in which there is described an electrically-operated motor vehicle improvements comprising a plurality of wheels arranged to be driven, a dynamotor forming an integral part of each such wheel, and electrical circuit connections between switch banks and dynamotors and batteries to control the operation of the dynamotors as motors according to the position of a selector switch. Again, the armature windings will have to be energized with a high current in order to produce a powerful motor, such high current will require large diameter cables to bring the energy from the batteries of the vehicle to the windings of the armature. As well known, such large diameter cables or wires are rigid, cumbersome and inconvenient.
Also known in the art, there are the following U.S. patents that describe different kinds of motor-wheels:
U.S. Pat. Nos. 638,643; 643,854; 2,506,146; 2,514,460; 2,581,551; 2,608,598; 3,566,165; 3,704,759; 3,792,742; 3,812,928; 3,892,300; 3,897,843; 4,021,690; 4,346,777; 4,389,586; 1,709,255; 2,335,398; and 3,548,965. PA1 a hollow shaft having a first opening at one end thereof and a second opening, said first opening receiving conductors from outside of said assembly; PA1 a stator coaxial with and fixedly attached to said shaft, said stator being provided with a hollow portion and coils; PA1 a rotor coaxial with said stator and mounted for rotation about said stator; PA1 converting means for converting an input electrical current to a variable AC electrical current, said converting means including power electronics fixedly mounted within said hollow portion, input terminals for receiving said input electrical current and output terminals for delivering said variable AC electrical current; PA1 whereby, to provide said variable AC current to said coils of said stator. PA1 Also, according to the present invention there is also provided: PA1 a motorized wheel assembly, comprising: PA1 a hollow shaft having a first opening at one end thereof and a second opening, said first opening being for receiving conductors from outside of said assembly; PA1 a stator having a central portion adapted to receive and be attached to said shaft, a support extending radially from said central portion, a peripheral circular pole piece comprising metallic strips wound with coils, and a hollow portion, said pole piece being fixed onto peripheral ends of said support, said support being provided with openings to reduce its weight; PA1 a rotor including a housing having a cylindrical wall having an inner surface provided with a magnetic means surrounding said stator and separated therefrom by an air-gap, said housing also comprising inner and outer walls mounted on both sides of said cylindrical wall, said second opening of said shaft being open into said housing; PA1 two bearings respectively associated with said walls, and respectively mounted on both sides of said shaft so that said rotor can be rotated with respect to said stator; and PA1 electrical converting means for converting an input electrical current to a variable AC electrical current, said converting means including power electronics fixedly mounted within said hollow portion, input terminals for receiving said input electrical current, an output terminals for delivering said variable AC electrical current, whereby, to provide said variable AC current to said coils of said stator; an assembly wherein said magnetic means of said rotor is made of a series of permanent magnets; said assembly further comprising a rim fixed onto said housing in a manner to extend around said cylindrical wall of said housing, and a layer made of elastomer and mounted between said rim and cylindrical wall, said rim being adapted to receive a tire; an assembly wherein said converting means comprises: PA1 a DC/AC converter having an input for receiving a direct current from said input terminals, and three outputs for generating three phase AC currents into said output terminals; and PA1 a microprocessor unit connected to said converter for controlling its operation; an assembly wherein: PA1 said stator is cross-shaped and has four arms; PA1 said converter is made of three converter units that generate respectively said three phase AC currents, said units being fixed respectively onto three of said four arms; and PA1 said microprocessor unit is fixed onto the fourth of said arms; said assembly further comprising two circular supply bus connected to said converter and microprocessor units, whereby said direct current can be distributed to said converter and microprocessor units by means of said bus; an assembly wherein said shaft has its first end provided with a connecting means by which said assembly can be connected to a supporting member; an assembly wherein said connecting means is made of an annular member having an outer edge regularly provided with recesses alternating with projections so that said annular member can be engaged and locked with a complementary part of the corresponding supporting member; an assembly in combination with said supporting member which is a knuckle-jointed connecting rod, wherein: PA1 said projections of said outer edge have width that varies in the circumferential direction, PA1 said complementary part of said knuckle-jointed connecting rod has an annular section having a sufficient diameter so that said annular section can be slid over said outer edge, PA1 said annular section has recesses and projections adapted to cooperate with the corresponding projections and recesses of said outer edge, said projections of said annular section having width that varies in the circumferential direction so that said annular section can be slid over said outer edge and rotated with respect with said outer edge to be wedged in an assembled position; said assembly in combination with said supporting member further comprising a key member having tongues that can be inserted in cavities that are produced when said annular section is rotated with respect to said outer edge to lock said outer edge with respect to said annular member; an assembly wherein said air-gap is positioned at a predetermined distance R.sub.1 from the central axis of said shaft, said rim has a surface for receiving a tire that is positioned at a predetermined distance R.sub.2 from the central axis of said shaft, and R.sub.1 /R.sub.2 is substantially between 0.65 and 0.91. PA1 a motorized wheel assembly, comprising: PA1 a hollow shaft having a first opening at one end thereof and a second opening, said first opening being for receiving conductors from outside of said assembly; PA1 a stator having a central portion adapted to receive and be attached to said shaft, a support extending radially from said central portion, a peripheral circular pole piece comprising metallic strips wound with coils, and a hollow portion, said pole piece being fixed onto peripheral ends of said support, said support being provided with openings to reduce its weight; PA1 a rotor including a housing having a cylindrical wall having an inner surface provided with a magnetic means surrounding said stator and separated therefrom by an air-gap, said housing also comprising inner and outer walls mounted on both sides of said cylindrical wall, said second opening of said shaft being open into said housing; PA1 two bearings respectively associated with said walls, and respectively mounted on both sides of said shaft so that said rotor can be rotated with respect to said stator; and PA1 electrical converting means for converting an input electrical current to a variable AC electrical current, said converting means including power electronics fixedly mounted within said hollow portion, input terminals for receiving said input electrical current, an output terminals for delivering said variable AC electrical current, whereby, to provide said variable AC current to said coils of said stator; PA1 a DC/AC converter having an input for receiving a direct current from said input terminals, and four outputs for generating respectively a DC current for said coil of said rotor, and three phase AC currents for said coils of said stator; PA1 a microprocessor unit connected to said converter for controlling its operation; an assembly wherein said converter comprises a first converter unit that generates said DC current for said coil of said rotor, and three converter units that generates respectively said three phase AC currents; an assembly wherein said shaft has its first end provided with a connecting means by which said assembly can be connected to a supporting member; an assembly wherein said connecting means is made of an annular member having an outer edge regularly provided with recesses alternating with projections so that said annular member can be engaged and locked with a complementary part of the corresponding supporting member; an assembly in combination with said supporting member which is a knuckle-jointed connecting rod, wherein: PA1 said projections of said outer edge have width that varies in the circumferential direction, PA1 said complementary part of said knuckle-jointed connecting rod has an annular section having a sufficient diameter so that said annular section can be slid over said outer edge, PA1 said annular section has recesses and projections adapted to cooperate with the corresponding projections and recesses of said outer edge, said projections of said annular section having width that varies in the circumferential direction so that said annular section can be slid over said outer edge and rotated with respect with said outer edge to be wedged in an assembled position; said assembly in combination with said supporting member further comprising a key member having tongues that can be inserted in cavities that are produced when said annular section is rotated with respect to said outer edge to lock said outer edge with respect to said annular member; an assembly wherein said air-gap is positioned at a predetermined distance R.sub.1 from the central axis of said shaft, said rim has a surface for receiving a tire that is positioned at a predetermined distance R.sub.2 from the central axis of said shaft, and R.sub.1 /R.sub.2 is substantially between 0.65 and 0.80. PA1 a motorized wheel assembly, comprising: PA1 a hollow shaft having a first opening at one end thereof and a second opening, said first opening being for receiving conductors from outside of said assembly; PA1 a stator having a central portion adapted to receive and be attached to said shaft, a support extending radially from said central portion, a peripheral circular pole piece comprising metallic strips wound with coils, and a hollow portion, said pole piece being fixed onto peripheral ends of said support, said support being provided with openings to reduce its weight; PA1 a rotor including a housing having a cylindrical peripheral wall having an inner surface provided with a magnetic means surrounding said stator and separated therefrom by an air-gap, said housing also comprising inner and outer walls mounted on both sides of said cylindrical peripheral wall, said second opening of said shaft being open into said housing; PA1 two bearings respectively associated with said walls, and respectively mounted on both sides of said shaft so that said rotor can be rotated with respect to said stator; and PA1 electrical converting means for converting an input electrical current to a variable AC electrical current, said converting means including power electronics fixedly mounted within said hollow portion, input terminals for receiving said input electrical current, an output terminals for delivering said variable AC electrical current, whereby, to provide said variable AC current to said coils of said stator; PA1 a DC/AC converter having an input for receiving a direct current from said input terminals, and three outputs for generating three phase AC currents into said output terminals; and PA1 a microprocessor unit connected to said converter for controlling its operation; an assembly wherein: PA1 said stator is cross-shaped and has four arms; PA1 said converter is mad of three converter units that generate respectively said three phase AC currents, said units being fixed respectively only three of said four arms; and PA1 said microprocessor unit is fixed onto the fourth of said arms; PA1 said projections of said outer edge have width that varies in the circumferential direction, PA1 said complementary part of said knuckle-jointed connecting rod has an annular section having a sufficient diameter so that said annular section can be slid over said outer edge, PA1 said annular section has recesses and projections adapted to cooperate with the corresponding projections and recesses of said outer edge, said projections of said annular section having width that varies in the circumferential direction so that said annular section can be slid over said outer edge and rotated with respect with said outer edge to be wedged in an assembled position; said assembly in combination with said supporting member further comprising a key member having tongues that can be inserted in cavities that are produced when said annular section is rotated with respect to said outer edge to lock said outer edge with respect to said annular member; an assembly wherein said air-gap is positioned at a predetermined distance R.sub.1 from the central axis of said shaft, said rim has a surface for receiving a tire that is positioned at a predetermined distance R.sub.2 from the central axis of said shaft, and R.sub.1 /R.sub.2 is substantially between 0.65 and 0.80.
None of the above-mentioned patents shows the necessary means for reducing the diameter of the wires of the power line between the motorized wheel assembly and the power supply when a powerful motorized wheel assembly is needed.
It is an object of the present invention to provide an electrically motorized wheel assembly wherein an variable AC current can be provided to coils of the stator of the assembly, and wherein relatively small diameter flexible and less cumbersome wires or cables can be used to supply electrical energy to the assembly even when a powerful motorized wheel assembly is needed.
It is also a further object obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly having a ratio R.sub.1 /R.sub.2 as close as possible to 1 where R.sub.1 is the distance between the air gap of the motorized assembly and the axis of rotation of the assembly, and R.sub.2 is the distance between the surface of a rim fixed onto the assembly, adapted to receive a tire, and the axis of rotation of the assembly.
It is also a further object of the present invention obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly that is provided with means for cooling down the assembly when it is operating.
It is a further object obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly having a reduced weight while being compatible with standard braking system, suspension system and steering system.
It is a further object obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly which is detachable from a suspension arm.